If you are using Microsoft Office XP or Microsoft Office 2003, you can change the view to HTML-Code using Microsoft Script Editor by pressing the Alt+Shift+F11 keys.

When the document is opened in the Microsoft Script Editor then search for “Password” and you will find something similar to this:
<w: DocumentProtection>ReadOnly</w: DocumentProtection>
<w: UnprotectPassword>9530C5F8</w: UnprotectPassword>

To remove the document’s form protection:
- remove the line containing ReadOnly and UnprotectPassword and then save the document using Ctrl+s, the protection should then be gone.